JP2004004096A - Temperature measuring wafer for heat treatment furnace for semiconductor wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature measuring wafer for use in testing temperature control of a heat treatment furnace of a semiconductor wafer, capable of simulating a temperature distribution of the wafer wherein thermocouples are suitably provided. <P>SOLUTION: The wafer includes a dummy wafer having same shape and material as an actual wafer, a large number of recesses distributed on the surface of the dummy wafer, and a large number of thermocouples each corresponding to the recesses. A hot contact part of the thermocouple is inserted into the corresponding recess while being brought into contact with the bottom part of the recess, and then is embedded in a heat resistant bonding agent filling the recess. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a temperature measurement wafer for a semiconductor wafer heat treatment furnace.
[0002]
[Prior art]
A semiconductor wafer is sliced and cut from a single crystal ingot, and then goes through various processing steps such as chamfering, cleaning, drying, heat treatment, and polishing to become a final product. For example, the heat treatment is performed to form a uniform thin film such as an oxide film, and a thermal diffusion processing device such as a CVD device or an epitaxial device is used.
[0003]
Therefore, the semiconductor wafer is subjected to heat treatment by a heat treatment furnace. Such a heat treatment furnace includes a horizontal heat treatment furnace in which a plurality of wafers are vertically arranged in a horizontal posture and a plurality of wafers. Vertical heat treatment furnaces are arranged in a standing posture. In any of the heat treatment furnaces, it is necessary to perform a uniform heat treatment on a plurality of wafers, so that control of a heater in the furnace is important. For example, a thermocouple is disposed on an inner wall of a reaction tube for accommodating a semiconductor wafer, and a technology for constantly controlling the internal temperature of the reaction tube (Japanese Patent Laid-Open No. 3-273719), or a thermocouple is disposed in a support portion for supporting a wafer. Techniques for controlling the heater temperature so that the peripheral temperature of the wafer is maintained at a predetermined appropriate value are known (JP-A-4-206816 and JP-A-5-136071).
[0004]
By the way, since the temperature control in the furnace as described above needs to be reflected in the actual temperature of the wafer placed in the furnace, before the heat treatment of the actual wafer (a genuine wafer which is a semiconductor wafer product), It is preferable to place a jig wafer (a pseudo wafer of the same type as the actual wafer) in a furnace and simulate the temperature of the jig wafer to control the heater in the furnace in advance.
[0005]
For this reason, for example, a jig wafer specially manufactured by embedding a thermocouple material inside a wafer (Japanese Patent Laid-Open No. Sho 62-165325), or a specially manufactured jig by sandwiching a thermocouple material between a pair of wafers. Jig wafers (Japanese Patent Laid-Open No. 62-165336) and jig wafers formed of quartz glass and having a thermocouple embedded therein (Japanese Utility Model Laid-Open No. 5-6340) have been proposed.
[0006]
[Problems to be solved by the invention]
Since the jig wafer described above must be able to simulate the temperature distribution of the actual wafer, it is designed to have the same shape and the same heat capacity as the actual wafer. However, it is not always easy to specially manufacture such a jig wafer.
[0007]
According to the findings of the present inventors, a semiconductor wafer (real wafer) is manufactured by slicing and cutting from a single crystal ingot, and various heat treatments are performed. However, due to the performance, shape, and the like of the heat treatment furnace, sufficient heat treatment and the like are not particularly performed on the wafers near the inlet of the furnace, and some wafers cannot be used as actual wafers. Therefore, if the present inventors utilize such a wafer that cannot be used as an actual wafer, the wafer having the same material and the same shape (the same thickness and the same contour shape) as the actual wafer is used as a wafer for temperature measurement (hereinafter, dummy wafer). ), And is most advantageous for performing the above-described simulation.
[0008]
By the way, in order to put such a dummy wafer into practical use as a temperature measurement wafer, it is necessary to provide a thermocouple on the dummy wafer, but there are various problems to be solved.
[0009]
For example, a technique is considered in which the hot junction of a thermocouple is bonded and fixed to the surface of the dummy wafer with an adhesive. In this case, the surface of the dummy wafer is overlaid with the adhesive, and the surface becomes uneven and the convex portion formed by the adhesive is used. Is formed, which has a different heat capacity from other portions, which is not preferable for simulation of temperature distribution.
[0010]
In addition, a technique of embedding and fixing a thermocouple in a sandwich shape between two dummy wafers is conceivable. In this case, not only is the processing complicated, but also not only at the hot junction part of the thermocouple but also at the element wire. Is sandwiched between wafers, it is extremely difficult to provide hot junctions at a plurality of locations.
[0011]
[Means for Solving the Problems]
The present invention provides a temperature-measuring wafer using the dummy wafer and solving the problems associated with the attachment of the thermocouple as described above. A dummy wafer of the same shape, a large number of concave portions scattered on the surface of the dummy wafer, and a large number of thermocouples corresponding to the concave portions, wherein a hot junction portion of the thermocouple is brought into contact with a bottom portion of the concave portion. The point is that the hot junction is buried in the heat-resistant adhesive filled in the recess.
[0012]
Further, the present invention is configured as a second means, because a real wafer and a dummy wafer of the same shape and the same material, a large number of concave portions scattered on the surface of the dummy wafer, and a large number of thermocouples corresponding to the concave portions. A pair of insertion holes penetrating the bottom of the recess at a distance from each other, and allowing the hot junction of the thermocouple to contact the bottom of the recess, and connecting each of the pair of thermocouple wires to the bottom of the recess. The hot junction is buried in a heat-resistant adhesive filled in the recess while being inserted through the pair of insertion holes, and an auxiliary recess overlapping the insertion hole of the recess is formed on the back surface of the dummy wafer. The auxiliary recess is formed and an auxiliary insertion hole is formed to penetrate the bottom of the auxiliary recess, and the thermocouple wire inserted through the insertion hole is folded back in the auxiliary recess, and the auxiliary recess is inserted into the auxiliary recess. In heat-resistant fixing agent Lies in the embedded folded portions of the thermocouple element.
[0013]
Further, the present invention is configured as a third means because a dummy wafer of the same shape and the same material as the actual wafer, a large number of concave portions scattered on the surface of the dummy wafer, and a large number of thermocouples corresponding to the concave portions. By forming the recess in a wedge-shaped cross section, the bottom width Wb and the opening width Wa of the recess are configured to satisfy Wb> Wa, and the hot junction of the thermocouple is brought into contact with the bottom of the recess. The point lies in that the hot junction is buried in the heat-resistant fixing agent filled in the concave portion.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
[0015]
In FIG. 1, a large number of recesses 2 are formed on a surface 1a of a dummy wafer 1 so as to be dotted. For example, a concave portion 2a located substantially at the center of the dummy wafer 1a, a plurality of concave portions 2b arranged at predetermined intervals on a virtual small diameter circle 3S concentrically drawn on the wafer 1a, and a concentric shape with the small diameter circle 3S. Are formed with a plurality of recesses 2c arranged at predetermined intervals on a virtual large diameter circle 3L drawn in FIG. In the case of the illustrated example, four concave portions 2b and four concave portions 2c are arranged at equal intervals on the small-diameter circle 3S and the large-diameter circle 3L, respectively, and the concave portion 2b on the small-diameter circle 3S and the large-diameter circle 3L are formed. By arranging the concave portions 2c so as to be out of phase with each other by about 45 degrees with respect to the circumference, the concave portions 2a, 2b, and 2c are evenly dispersed with respect to the entire dummy wafer 1, and the entire dummy wafer 1 is dispersed by a thermocouple described later. It is configured to be able to measure a temperature distribution over a range.
[0016]
A hot junction of a thermocouple 4 is inserted into each of the recesses 2, and the recess is filled with a heat-resistant adhesive in a state where the hot junction is brought into contact with the bottom of the recess. The contact part is buried. A pair of strands 4b, 4b of each thermocouple 4 is led to a connector 5, where it is connected to a thermocouple or compensating lead 6. Preferably, the strand 4b of the thermocouple extending from the hot junction is appropriately coated with a heat-resistant coating material.
[0017]
Normally, in a heat treatment furnace for semiconductor wafers, the furnace temperature is 800 to 1000 ° C., so that the resin-based adhesive cannot withstand the furnace temperature. For this reason, the heat-resistant fixing agent is preferably an inorganic heat-resistant cement. In particular, when a heat-resistant cement containing silica and alumina as a main component is used, the coefficient of thermal expansion is low, the peel resistance is excellent, and the viscosity is high, so that drying is quick. In addition, it satisfies the heat resistance temperature of about 1600 ° C.
[0018]
The dummy wafer 1 is, for example, a disk having a diameter of 200 mmφ and a thickness of 0.76 mm sliced from a single crystal silicon ingot, and the concave portion 2 is formed to have a diameter of about 3 mmφ by counterbore processing the surface of the dummy wafer 1. Are formed. Then, with the hot junction portion of the thermocouple buried in the recess 2 and in contact with the bottom of the recess 2, the recess 2 is filled with a heat-resistant fixing agent and solidified. At this time, since the heat-resistant adhesive is filled in the concave portion 2, it is preferable that the surface of the filled heat-resistant adhesive and the surface of the dummy wafer be flat without protruding from the surface of the dummy wafer 1.
[0019]
(First embodiment)
FIG. 2 shows a first embodiment of a connection mode between the concave portion 2 and the thermocouple 4, and a pair of insertion holes 8, 8 penetrating at intervals from each other are formed in the bottom portion 7 of the concave portion 2 by cutting. Have been. In the illustrated embodiment in which the recess 2 is formed as a circular recess, the pair of insertion holes 8, 8 are provided in the diametrical direction of the recess 2 and near the periphery of the recess 2.
[0020]
Therefore, the thermocouple 4 causes the hot junction 4a to contact the bottom 7 of the recess 2 and inserts each of the pair of strands 4b, 4b into the pair of insertion holes 8, 8 from the surface 1a side of the dummy wafer 1. The concave portion 2 is filled with a heat-resistant adhesive 9 in this state, and the hot junction 4a is embedded in the solidified heat-resistant adhesive.
[0021]
According to the first embodiment, when the thermocouple 4 is buried in the concave portion 2, first, each of the pair of strands 4 b, 4 b is inserted into the insertion holes 8, 8 from the front surface 1 a side of the dummy wafer 1. After the wires 4b, 4b are pulled out in the insertion direction after being inserted into the back surface 1b side of 1, the hot junction portion 4a is securely supported by the bottom 7 of the concave portion 2.
[0022]
In addition, since the thermocouple 4 has the vicinity of the hot junction 4a wound around the concave portion 2 in the direction in which the wires 4b and 4b are drawn in, the thermocouple 4 is dropped from the dummy wafer 1 by an external force. There is no fear.
[0023]
(Second embodiment)
FIG. 3 shows a second embodiment of the connection mode between the recess 2 and the thermocouple 4. The bottom 7 of the recess 2 provided on the front surface 1 a of the dummy wafer 1 is located in the diameter direction of the recess 2 and A pair of through holes 8, 8 are formed near the periphery of the concave portion 2 and penetrate therethrough. This point is almost the same as that of the first embodiment, but furthermore, a counterbore is formed on the back surface 1b of the dummy wafer 1. Thus, an auxiliary recess 10 overlapping each insertion hole 8 of the recess 2 is formed, and an auxiliary insertion hole 12 penetrating through the bottom 11 of the auxiliary recess 10 is formed.
[0024]
Then, the thermocouple 4 inserts each of the pair of strands 4b, 4b from the front surface 1a side of the dummy wafer 1 into the pair of insertion holes 8, 8, and inserts them into the back surface 1b side of the dummy wafer 1. At this time, if the wires 4b, 4b are pulled in the insertion direction, the hot junction 4a is supported on the bottom 7 of the concave portion 2. Next, the wires 4b, 4b are inserted into the folded auxiliary insertion holes 12 in the auxiliary recesses 10 and inserted into the surface 1a of the dummy wafer 1, and the wires 4b, 4b are pulled in the insertion direction. The folded portions 4b and 4b are engaged with the bottom 11 of the auxiliary recess 10. In this state, the concave portion 2 and the auxiliary concave portions 10 and 10 are filled with the heat-resistant fixing agent 9, the solidified heat-resistant adhesive is buried in the concave portion 2, and the solidified heat-resistant fixing portion 4 a is buried in the auxiliary concave portion 10. The folded portion of the wire 4b is embedded in the agent.
[0025]
(Third embodiment)
FIG. 4 shows a third embodiment of the connection mode between the concave portion 2 and the thermocouple 4. The concave portion 2 provided on the surface 1a of the dummy wafer 1 is formed in a wedge-shaped cross section, and the width of the bottom 7 of the concave portion 2 is shown. Wb and the width Wa of the opening are set so that Wb> Wa.
[0026]
Then, the thermocouple 4 is brought into contact with the hot junction portion 4a with the bottom portion 7 of the concave portion 2, and in this state, the concave portion 2 is filled with the heat resistant fixing agent 9, whereby the hot junction portion 4a is put into the solidified heat resistant fixing agent. It is buried. The pair of strands 4 b, 4 b of the thermocouple 4 are led out of the heat-resistant fixing agent 9. Therefore, in the case of the third embodiment, the dummy wafer 1 placed in the heat treatment furnace receives the heat of the heater on the back surface 1b and arranges the wires 4b, 4b of the thermocouple 4 on the front surface 1a.
[0027]
【The invention's effect】
According to the first aspect of the present invention, since the dummy wafer 1 is made of the same material as the actual wafer, it is possible to optimally simulate the actual temperature distribution of the actual wafer. Then, such a dummy wafer 1 can be easily obtained by effectively utilizing a wafer which has been made unproductable.
[0028]
Then, in providing a temperature measurement wafer for a semiconductor wafer heat treatment furnace, it is possible to solve the above-mentioned problems associated with mounting a thermocouple. That is, when a large number of thermocouples 4 are provided on the dummy wafer 1, the concave portion 2 is formed in the dummy wafer 1, and the hot junction 4 a of the thermocouple 4 is brought into contact with the bottom 7 of the concave portion 2, and Since the hot junction 4a is buried with the filled heat-resistant adhesive 9, the heat-resistant adhesive 9 is hardened in a state of being restrained by the concave portion 2, and is hardly peeled off by being locked in the concave portion 2; Is prevented from dropping from the dummy wafer 1. Further, when the hot junction of the thermocouple is directly fixed to the surface of the wafer with an adhesive, a convex portion is formed on the surface of the wafer, whereas according to the present invention, a pair of thermocouples is provided. With the configuration in which the heat resistant fixing agent 9 is filled in the concave portion 2 in which the hot junction portion 4a is buried while the wires 4b, 4b are inserted through the pair of insertion holes 8, 8, the surface 1a of the dummy wafer 1 is Such a convex portion is not formed, and the temperature distribution of the dummy wafer 1 can be suitably simulated.
[0029]
According to the second aspect of the present invention, a pair of insertion holes 8, 8 penetrating through the bottom portion 7 of the concave portion 2 at a distance from each other are opened, and the hot junction portion 4 a of the thermocouple 4 is connected to the concave portion. 2 with the pair of thermocouple wires 4b, 4b inserted through the pair of insertion holes 8, 8, respectively, and with the heat-resistant adhesive 9 filled in the recess 2, the hot junction is inserted. Since the configuration is such that the portion 4a is buried, the hot junction portion 4a can be securely contacted with the bottom 7 of the concave portion 2, and the thermocouple 4 is moved in the direction in which the wires 4b, 4b are drawn. Since the vicinity of the hot junction portion 4a is engaged with the concave portion 2 in a winding manner, there is no possibility that the thermocouple 4 will fall off the dummy wafer 1 due to an external force. And the thermocouple 4 can be firmly implanted. Further, in addition to such a configuration, the present invention described in claim 2 further forms an auxiliary recess 10 overlapping each of the insertion holes 8, 8 of the recess 2 on the back surface 1 b of the dummy wafer 1. An auxiliary insertion hole 12 that penetrates the bottom 11 of the auxiliary recess 10 is opened, and the thermocouple wire 4b inserted through the insertion hole 8 is folded back in the auxiliary recess 10 to be inserted into the auxiliary insertion hole 12, and in this state, Since the folded portion of the thermocouple wire 4b is buried by the heat-resistant fixing agent 9 filled in the auxiliary recess 10, the planting strength of the thermocouple 4 is further enhanced.
[0030]
According to the third aspect of the present invention, the width Wb of the bottom 7 of the recess and the width Wa of the opening are configured such that Wb> Wa by forming the recess 2 in a wedge-shaped cross section, and the hot junction of the thermocouple 4 is formed. Since the hot junction 4a is buried with the heat-resistant adhesive 9 filled in the recess 7 in a state where the portion 4a is in contact with the bottom 7 of the recess 2, the structure is simple, but the recess has a wedge-shaped cross section. The heat-resistant fixing agent 9 can be locked in a locking manner with respect to 2, so that the thermocouple 4 can be firmly implanted.
[Brief description of the drawings]
FIG. 1 shows one embodiment of the present invention, wherein (A) is a plan view and (B) is a side view.
2A and 2B show a first embodiment of the present invention, wherein FIG. 2A is a plan view showing a concave portion, FIG. 2B is a sectional view showing a concave portion and a thermocouple, and FIG. 2C is a state where a thermocouple is implanted in the concave portion. FIG.
3A and 3B show a second embodiment of the present invention, wherein FIG. 3A is a plan view showing a concave portion, FIG. 3B is a sectional view showing a concave portion and a thermocouple, and FIG. 3C is a state where a thermocouple is implanted in the concave portion. FIG.
4A and 4B show a third embodiment of the present invention, wherein FIG. 4A is a plan view showing a concave portion, and FIG. 4B is a sectional view showing a state where a thermocouple is implanted in the concave portion.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 dummy wafer 2 recess 4 thermocouple 7 bottom of recess 8 insertion hole 9 heat-resistant adhesive 10 auxiliary recess 11 bottom 12 of auxiliary recess 12 auxiliary insertion hole

Claims (3)

A dummy wafer of the same shape and the same material as the real wafer, a large number of concave portions scattered on the surface of the dummy wafer, and a large number of thermocouples corresponding to the concave portions,
A temperature measuring wafer for a semiconductor wafer heat treatment furnace, wherein the hot junction is buried in a heat-resistant adhesive filled in the recess while the hot junction of the thermocouple is in contact with the bottom of the recess. . A dummy wafer of the same shape and the same material as the real wafer, a large number of concave portions scattered on the surface of the dummy wafer, and a large number of thermocouples corresponding to the concave portions,
Opening a pair of insertion holes penetrating the bottom of the recess at an interval from each other, making the hot junction of the thermocouple contact the bottom of the recess, and connecting each of the pair of thermocouple wires to the pair of thermocouples. In the state of being inserted through the insertion hole, the hot junction portion is buried in a heat-resistant adhesive filled in the concave portion,
Further, an auxiliary concave portion overlapping with each of the insertion holes of the concave portion is formed on the back surface of the dummy wafer, and an auxiliary insertion hole that penetrates the bottom of the auxiliary concave portion is opened to assist the thermocouple wire inserted through the insertion hole. A temperature measuring wafer for a semiconductor wafer heat treatment furnace, wherein a folded portion of the thermocouple wire is buried in a heat-resistant adhesive filled in the auxiliary recess while being inserted into the folding auxiliary insertion hole in the recess. . A dummy wafer of the same shape and the same material as the real wafer, a large number of concave portions scattered on the surface of the dummy wafer, and a large number of thermocouples corresponding to the concave portions,
By forming the recess in a wedge-shaped cross section, the bottom width Wb and the opening width Wa of the recess are configured such that Wb> Wa,
A temperature measuring wafer for a semiconductor wafer heat treatment furnace, wherein the hot junction is buried in a heat-resistant adhesive filled in the recess while the hot junction of the thermocouple is in contact with the bottom of the recess. .

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